<template>
  <div class="com-container">
    <div class="com-chart" ref="dv"></div>
  </div>
</template>

<script>
export default {
  data () {
    return {
      chartInstance: '',
      allData: [],
      startValue: 0,
      endValue: 9,
      timerId: null,
      titleFontSize: 0
    }
  },
  mounted () {
    this.initChart()
    this.getData()
    window.addEventListener('resize', this.screenAdapter)
    this.screenAdapter()
  },
  destroyed () {
    window.removeEventListener('resize', this.screenAdapter)
    clearInterval(this.timerId)
  },
  methods: {
    initChart () {
      this.chartInstance = this.$echarts.init(this.$refs.dv, 'chalk')
      const initOption = {
        title: {
          text: '▎ 地区销售排行',
          left: 20,
          top: 20
        },
        grid: {
          top: '40%',
          left: '5%',
          bottom: '5%',
          right: '5%',
          containLabel: true
        },
        tooltip: {
          show: true
        },
        xAxis: {
          type: 'category'
        },
        yAxis: {
          type: 'value'
        },
        series: [{
          type: 'bar'
        }]
      }
      this.chartInstance.setOption(initOption)
      this.chartInstance.on('mouseover', () => {
        clearInterval(this.timerId)
      })
      this.chartInstance.on('mouseout', () => {
        this.startInterval()
      })
    },
    async getData () {
      const {
        data: res
      } = await this.$http.get('./data/rank.json')
      this.allData = res
      this.allData.sort((a, b) => {
        return b.value - a.value
      })
      this.updateChart()
      this.startInterval()
    },
    updateChart () {
      const colorArr = [
        ['#0BA82C', '#4FF778'],
        ['#2E72BF', '#23E5E5'],
        ['#5052EE', '#AB6EE5']
      ]
      const provinceArr = this.allData.map(item => {
        return item.name
      })
      const valueArr = this.allData.map(item => {
        return item.value
      })
      const dataOption = {
        xAxis: {
          data: provinceArr
        },
        yAxis: {
          max: (this.allData[0].value) + 40
        },
        dataZoom: {
          show: false,
          startValue: this.startValue,
          endValue: this.endValue
        },
        series: [{
          data: valueArr,
          itemStyle: {
            color: arg => {
              var targetColorArr = colorArr
              if (arg.value >= 300) {
                targetColorArr = colorArr[0]
              } else if (arg.value >= 200) {
                targetColorArr = colorArr[1]
              } else {
                targetColorArr = colorArr[2]
              }
              return new this.$echarts.graphic.LinearGradient(0,
                1, 0, 0, [{
                  offset: 0,
                  color: targetColorArr[0]
                }, {
                  offset: 1,
                  color: targetColorArr[1]
                }
                ])
            },
            barBorderRadius: [33, 33, 0, 0]
          }
        }]
      }
      this.chartInstance.setOption(dataOption)
    },
    screenAdapter () {
      const titleFontSize = this.$refs.dv.offsetWidth / 100 * 3.6
      const adapterOption = {
        title: {
          textStyle: {
            fontSize: titleFontSize
          }
        },
        series: [{
          barWidth: titleFontSize,
          itemStyle: {
            barBorderRadius: [titleFontSize, titleFontSize, 0, 0]
          }
        }]
      }
      this.chartInstance.setOption(adapterOption)
      this.chartInstance.resize()
    },
    startInterval () {
      if (this.timerId) {
        clearInterval(this.timerId)
      }
      this.timerId = setInterval(() => {
        this.startValue++
        this.endValue++
        if (this.endValue > this.allData.length - 1) {
          this.startValue = 0
          this.endValue = 9
        }
        this.updateChart()
      }, 3000)
    }
  }

}
</script>

<style>
</style>
